[sdiy] MG-1 first mods, VC res

[KA4HJH]

> I've got my 33vct transformer ready to try
>today. I hope this isn't too
>> little! People typically suggest leaving a bit of headroom >so I'd prefer
>35v, but I don't have a convenient stash of >transformers here.
>>
>Well, 33V ct gives 46.2 or so peak voltage, so I hope
>at least your input caps can handle it!
>The other possibility is that the original transformers
>were over voltage, since the MG-1 was designed to a price (Paul chrieber has
>posted before about this!) so
>maybe those transformers just happened to be a 'good deal'.

This is what I always assumed. If they saved any money by using this
particular transformer it was at least partially offset by having to use
higher voltage capacitors.

IIRC, the peak voltage on the filter caps will be the RMS x (2 x SQRT(2)),
or in this case 19V (RMS) x 1.414, which just happens to be just under 27V
DC on each side. So it would appear that everything is close to *normal*
here (according to Paul's former bosses at Radio Shack, anyway).

I've always felt that the 38V transformer is a bit high and it's no wonder
the regulators run hot. I agree that 35-36V would probably be ideal. You
can try 33V, it may or may not work. There's only one way to find out.

-- 

Terry Bowman, KA4HJH
"The Mac Doctor"